339 lines
10 KiB
TypeScript
339 lines
10 KiB
TypeScript
/*
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* Copyright 2019 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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/* This file implements gRFC A2 and the service config spec:
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* https://github.com/grpc/proposal/blob/master/A2-service-configs-in-dns.md
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* https://github.com/grpc/grpc/blob/master/doc/service_config.md. Each
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* function here takes an object with unknown structure and returns its
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* specific object type if the input has the right structure, and throws an
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* error otherwise. */
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/* The any type is purposely used here. All functions validate their input at
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* runtime */
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/* eslint-disable @typescript-eslint/no-explicit-any */
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import * as os from 'os';
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import {
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LoadBalancingConfig,
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validateLoadBalancingConfig,
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} from './load-balancer';
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export interface MethodConfigName {
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service: string;
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method?: string;
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}
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export interface Duration {
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seconds: number;
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nanos: number;
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}
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export interface MethodConfig {
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name: MethodConfigName[];
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waitForReady?: boolean;
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timeout?: Duration;
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maxRequestBytes?: number;
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maxResponseBytes?: number;
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}
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export interface ServiceConfig {
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loadBalancingPolicy?: string;
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loadBalancingConfig: LoadBalancingConfig[];
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methodConfig: MethodConfig[];
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}
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export interface ServiceConfigCanaryConfig {
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clientLanguage?: string[];
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percentage?: number;
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clientHostname?: string[];
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serviceConfig: ServiceConfig;
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}
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/**
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* Recognizes a number with up to 9 digits after the decimal point, followed by
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* an "s", representing a number of seconds.
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*/
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const TIMEOUT_REGEX = /^\d+(\.\d{1,9})?s$/;
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/**
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* Client language name used for determining whether this client matches a
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* `ServiceConfigCanaryConfig`'s `clientLanguage` list.
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*/
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const CLIENT_LANGUAGE_STRING = 'node';
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function validateName(obj: any): MethodConfigName {
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if (!('service' in obj) || typeof obj.service !== 'string') {
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throw new Error('Invalid method config name: invalid service');
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}
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const result: MethodConfigName = {
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service: obj.service,
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};
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if ('method' in obj) {
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if (typeof obj.method === 'string') {
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result.method = obj.method;
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} else {
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throw new Error('Invalid method config name: invalid method');
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}
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}
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return result;
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}
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function validateMethodConfig(obj: any): MethodConfig {
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const result: MethodConfig = {
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name: [],
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};
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if (!('name' in obj) || !Array.isArray(obj.name)) {
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throw new Error('Invalid method config: invalid name array');
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}
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for (const name of obj.name) {
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result.name.push(validateName(name));
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}
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if ('waitForReady' in obj) {
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if (typeof obj.waitForReady !== 'boolean') {
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throw new Error('Invalid method config: invalid waitForReady');
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}
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result.waitForReady = obj.waitForReady;
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}
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if ('timeout' in obj) {
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if (typeof obj.timeout === 'object') {
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if (
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!('seconds' in obj.timeout) ||
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!(typeof obj.timeout.seconds === 'number')
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) {
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throw new Error('Invalid method config: invalid timeout.seconds');
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}
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if (
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!('nanos' in obj.timeout) ||
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!(typeof obj.timeout.nanos === 'number')
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) {
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throw new Error('Invalid method config: invalid timeout.nanos');
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}
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result.timeout = obj.timeout;
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} else if (
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typeof obj.timeout === 'string' &&
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TIMEOUT_REGEX.test(obj.timeout)
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) {
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const timeoutParts = obj.timeout
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.substring(0, obj.timeout.length - 1)
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.split('.');
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result.timeout = {
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seconds: timeoutParts[0] | 0,
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nanos: (timeoutParts[1] ?? 0) | 0,
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};
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} else {
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throw new Error('Invalid method config: invalid timeout');
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}
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}
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if ('maxRequestBytes' in obj) {
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if (typeof obj.maxRequestBytes !== 'number') {
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throw new Error('Invalid method config: invalid maxRequestBytes');
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}
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result.maxRequestBytes = obj.maxRequestBytes;
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}
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if ('maxResponseBytes' in obj) {
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if (typeof obj.maxResponseBytes !== 'number') {
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throw new Error('Invalid method config: invalid maxRequestBytes');
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}
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result.maxResponseBytes = obj.maxResponseBytes;
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}
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return result;
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}
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export function validateServiceConfig(obj: any): ServiceConfig {
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const result: ServiceConfig = {
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loadBalancingConfig: [],
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methodConfig: [],
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};
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if ('loadBalancingPolicy' in obj) {
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if (typeof obj.loadBalancingPolicy === 'string') {
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result.loadBalancingPolicy = obj.loadBalancingPolicy;
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} else {
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throw new Error('Invalid service config: invalid loadBalancingPolicy');
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}
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}
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if ('loadBalancingConfig' in obj) {
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if (Array.isArray(obj.loadBalancingConfig)) {
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for (const config of obj.loadBalancingConfig) {
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result.loadBalancingConfig.push(validateLoadBalancingConfig(config));
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}
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} else {
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throw new Error('Invalid service config: invalid loadBalancingConfig');
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}
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}
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if ('methodConfig' in obj) {
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if (Array.isArray(obj.methodConfig)) {
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for (const methodConfig of obj.methodConfig) {
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result.methodConfig.push(validateMethodConfig(methodConfig));
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}
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}
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}
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// Validate method name uniqueness
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const seenMethodNames: MethodConfigName[] = [];
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for (const methodConfig of result.methodConfig) {
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for (const name of methodConfig.name) {
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for (const seenName of seenMethodNames) {
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if (
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name.service === seenName.service &&
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name.method === seenName.method
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) {
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throw new Error(
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`Invalid service config: duplicate name ${name.service}/${name.method}`
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);
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}
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}
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seenMethodNames.push(name);
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}
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}
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return result;
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}
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function validateCanaryConfig(obj: any): ServiceConfigCanaryConfig {
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if (!('serviceConfig' in obj)) {
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throw new Error('Invalid service config choice: missing service config');
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}
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const result: ServiceConfigCanaryConfig = {
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serviceConfig: validateServiceConfig(obj.serviceConfig),
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};
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if ('clientLanguage' in obj) {
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if (Array.isArray(obj.clientLanguage)) {
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result.clientLanguage = [];
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for (const lang of obj.clientLanguage) {
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if (typeof lang === 'string') {
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result.clientLanguage.push(lang);
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} else {
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throw new Error(
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'Invalid service config choice: invalid clientLanguage'
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);
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}
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}
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} else {
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throw new Error('Invalid service config choice: invalid clientLanguage');
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}
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}
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if ('clientHostname' in obj) {
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if (Array.isArray(obj.clientHostname)) {
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result.clientHostname = [];
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for (const lang of obj.clientHostname) {
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if (typeof lang === 'string') {
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result.clientHostname.push(lang);
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} else {
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throw new Error(
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'Invalid service config choice: invalid clientHostname'
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);
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}
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}
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} else {
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throw new Error('Invalid service config choice: invalid clientHostname');
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}
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}
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if ('percentage' in obj) {
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if (
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typeof obj.percentage === 'number' &&
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0 <= obj.percentage &&
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obj.percentage <= 100
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) {
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result.percentage = obj.percentage;
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} else {
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throw new Error('Invalid service config choice: invalid percentage');
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}
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}
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// Validate that no unexpected fields are present
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const allowedFields = [
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'clientLanguage',
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'percentage',
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'clientHostname',
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'serviceConfig',
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];
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for (const field in obj) {
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if (!allowedFields.includes(field)) {
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throw new Error(
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`Invalid service config choice: unexpected field ${field}`
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);
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}
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}
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return result;
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}
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function validateAndSelectCanaryConfig(
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obj: any,
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percentage: number
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): ServiceConfig {
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if (!Array.isArray(obj)) {
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throw new Error('Invalid service config list');
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}
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for (const config of obj) {
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const validatedConfig = validateCanaryConfig(config);
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/* For each field, we check if it is present, then only discard the
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* config if the field value does not match the current client */
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if (
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typeof validatedConfig.percentage === 'number' &&
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percentage > validatedConfig.percentage
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) {
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continue;
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}
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if (Array.isArray(validatedConfig.clientHostname)) {
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let hostnameMatched = false;
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for (const hostname of validatedConfig.clientHostname) {
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if (hostname === os.hostname()) {
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hostnameMatched = true;
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}
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}
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if (!hostnameMatched) {
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continue;
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}
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}
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if (Array.isArray(validatedConfig.clientLanguage)) {
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let languageMatched = false;
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for (const language of validatedConfig.clientLanguage) {
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if (language === CLIENT_LANGUAGE_STRING) {
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languageMatched = true;
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}
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}
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if (!languageMatched) {
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continue;
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}
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}
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return validatedConfig.serviceConfig;
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}
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throw new Error('No matching service config found');
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}
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/**
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* Find the "grpc_config" record among the TXT records, parse its value as JSON, validate its contents,
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* and select a service config with selection fields that all match this client. Most of these steps
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* can fail with an error; the caller must handle any errors thrown this way.
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* @param txtRecord The TXT record array that is output from a successful call to dns.resolveTxt
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* @param percentage A number chosen from the range [0, 100) that is used to select which config to use
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* @return The service configuration to use, given the percentage value, or null if the service config
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* data has a valid format but none of the options match the current client.
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*/
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export function extractAndSelectServiceConfig(
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txtRecord: string[][],
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percentage: number
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): ServiceConfig | null {
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for (const record of txtRecord) {
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if (record.length > 0 && record[0].startsWith('grpc_config=')) {
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/* Treat the list of strings in this record as a single string and remove
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* "grpc_config=" from the beginning. The rest should be a JSON string */
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const recordString = record.join('').substring('grpc_config='.length);
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const recordJson: any = JSON.parse(recordString);
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return validateAndSelectCanaryConfig(recordJson, percentage);
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}
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}
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return null;
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}
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